Circuit interrupter



1 2- B. P. BAKER CIRCUIT INTERRUPTER Filed March 19, 1942 '2 Sheets-Sheet l Mag/who Material WITNESSES:

ENVENTOR Barzjamzh PBaker.

BY 5A1 q ATTORNEY Patented Dec. 1, 1942 UNITED STATES PATENT ()FFICE CIRCUIT INTERRUPTER Pennsylvania Application March 19, 1942, Serial No. 435,380

32 Claims.

This invention relates to circuit interrupters in general, and, more particularly, to circuit interrupters of the type which utilize an are restraining channel or slot into which the arc is moved during low instantaneous values of current. After the arc has been moved into said channel or slot it is subjected to strong deionizing action by a turbulent intermixing of unionized liquid or gaseous particles with the arc stream.

Certain modifications of the present invention are set forth and claimed in my copending application Serial No. 437,001, filed March 31, 1942, entitled Circuit interrupters, and assigned to the assignee of the present application It is an object of the invention to provide a circuit interrupter of the fluid flow type in which the relation between the fluid flow and the arc to be extinguished is varied in accordance with the instantaneous value of the arc current, so that the arc will be subjected to more effective flow near current zero than near the peaks of the current wave.

Another object of the invention is to provide an arc chamber with a vent through which fluid flows, and means for moving the are away from the vent during high instantaneous values of arc current.

The instant invention is, in certain of its aspects, an improvement of the invention set forth and broadly claimed in Patent 2,138,382, issued November 29, 1938, to Winthrop M. Leeds and Ennio Ortensi and assigned to the assignee of this application. For purposes of illustration only the present invention will be described as embodied in a liquid arc extinguishing structure of the type described and claimed in the aforesaid patent. However, the invention is not limited in its application to a liquid type breaker, but in some of its aspects may readily be applied to a gas blast type breaker, particularly a gas blast type breaker having an arc restraining channel or slot, the Walls of which are composed of a material which emits a gas or a vapor upon being subjected to an arc.

In the aforesaid patent it was pointed out that driving the are into a restricted passage and subjecting it to strong cross blasts of oil and gas immediately following the establishment of the arc, irrespective of the instantaneous current conditions, resulted in high are voltage, high internal pressure caused by excessive gas genera tion, and a harmful effect on the interrupting ability of the arc rupturing device. An improved method of arc extinction was advanced which consisted in three steps, these steps either being taken successively or in combination, preferably the latter.

First, during the greater portion of time are current is flowing, particularly in the region of the peak of the current wave, the arc should be disturbed as little as possible by cross blasts, restricting walls, or strong magnetic action, so as to keep the arc voltage and the consequent gas generation as low as possible. Second, vents, passages and liquid flow should be arranged to drive the products of decomposition of the are out of the arcing chamber as fast as they are formed so as to maintain high dielectric in the arcing chamber and keep the internal pressure within the arcing chamber reasonably low. Third, just prior to current zero, when the arc current is relatively low, strong deionizing action should be brought into existence, as for instance subjecting the are to turbulent cross blasts of liquid and gas, confining the are within a restricted passage, or rapidly moving or lengthening the arc.

In the aforesaid patent the arc was initially drawn in a relatively large arcing slot, said slot being formed by a stack of suitably formed insulating plates. This slot communicated with an adjacently disposed narrow arcing slot, the width of said narrow arcing slot being such that during the peak of the alternating current wave the cross-section of the arc column was too large topermit the arc column to be forced from the relatively large slot into the narrow arcing slot. The are stream was hence forced to play adjacent the entrance to the narrow arcing slot during high instantaneous values of current. The arc was biased toward the narrow arcing slot by the presence of a plurality of U-shaped inserts of magnetic material. The biasing force exerted by the magnetic plates in a direction toward the narrow arcing slot was a maximum during the peak of the current wave, but because of the large cross-section of the arc column at this time the arc column was not permitted to enter the narrow arcing slot.

During the time the are stream played outside the entrance to the narrow arcing slot it was subjected to a longitudinal flow of liquid caused by the piston action of the moving contact. This longitudinal flow was freely vented out of the arcing chamber through vents formed in the upper arcing horn of the breaker. Consequently, products of decomposition caused by the action of the are upon the liquid were quickly removed from the arcing region to maintain a high dielectric strength in this region.

When the arcing current reached relatively low instantaneous values, that is approached a current zero, the cross-section thereof was sufficiently small to permit it to be forced by the biasing action of the magnetic plates into the narrow arcing slot. In this narrow arcing slot the arc was subjected to strong cross blasts of unionized liquid and gaseous particles. Complete are extinction soon followed, vents at the remote end of the narrow arcing slot serving to vent products of decomposition and the flow being created, as mentioned before, by the piston action of the moving contact. Some of the insulating plates forming the stack in which interruption took place were so shaped as to provide oil pockets disposed in the walls defining the narrow arcing slot. The oil stored in these oil pockets was re acted upon by the arc to produce a turbulent intermixing of unionized oil and gas particles through the arc stream resulting in arc extinction and hence circuit interruption.

Prior to the entrance of the are into the narrow arcing slot it was positioned adjacent the the entrance thereof. Consequently, one disadvantage of the structure described in the aforesaid patent was that the walls forming the entrance to the narrow arcing slot were subject to wearing and burning by the heat of the arc. The wearing and burning or the walls forming the entrance to the narrow arcing slot resulted in enlarging the entrance to the narrow arcing slot, and consequently tending to change the characteristics thereof by permitting arcs of larger cross-sectional area to be forced into the narrow arcing slot. In other words, by the biasing action produced by the U-shaped magnetic plates the arc was forced to play at the entrance to the narrow arcing slot during high instantaneous values of current with a resulting burning and a consequent enlarging of the entrance to the narrow arcing slot.

It is one of the objects of the present invention to provide an arc extinguishing unit of the type described in the aforesaid patent with means for holding the arc durin high instantaneous values of current away from the entrance to the narrow arcing slot until relatively low instantaneous values of arcing current. At this time the force holding the arc away from the narrow arcing slot will be diminished to permit at least two other forces to bias the are into the narrow arcing slot. One of these forces will be the flow of oil or other suitable arc extinguishing liquid resulting from piston action of the moving contact, and the other force is the inherent tendency of the arc itself to elongate and curve into the narrow arcing slot in the direction of the vents.

A more specific object of the present invention is the provision of an arc extinguishing unit simiiar to that described in the aforesaid patent composed of a plurality of insulating plates, some of said insulating plates containing U-shaped magnetic inserts, the disposition of which are such that the arc is held away from the entrance to the narrow arcing slot during high instantaneous values of current.

Another object of the present invention is the provision of an arc extinguishing unit of the aforesaid type composed of a plurality of insulating plates, some of said plates containing Llshaped magnetic inserts tending to hold the are away from the narrow arcing slot and some of said insulating plates containing U-sthaped magnetic inserts tending to bias the are into the narrow arcing slot. By suitable disposition and shape of said U-shaped magnetic inserts the lateral movement of the arc can be controlled within said arc extinguishing unit.

A more specific object of the present invention is the provision of an arc extinguishing structure of the narrow slot type, operating in a liquid or gaseous medium, and provided with one or more substantially U-shaped magnetic plates with a relatively small air gap to bias the arc into the narrow arcing slot, and one or more other substantially U-shaped magnetic plates with a. relatively large air gap to bias the arc away from the entrance to the narrow arcing slot The cross-sectional area of the magnetic plates biasing the arc into the narrow arcing slot will be less than the cross-sectional area of the magnetic plates biasing the are away from the entrance to the narrow arcing slot. Hence during relatively high instantaneous Values of current the inward biasing magnetic plates will substantially saturate, but the outward biasing magnetic plates will not, thus permitting the outward biasing magnetic plates to predominate during relatively high instantaneous values of current to hold the arc column away from the entrance to the narrow arcing slot. During relatively low instantaneous values of arcing current none of said magnetic plates will saturate, and because of the smaller air gap the inward biasing magnetic plates will predominate to force the arc during relatively low instantaneous values of current into the narrow arcing slot to effect extinction of the arc and a consequent circuit interruption.

It is a further object of the present invention to provide an a "c extinguishing unit composed of a plurality of superimposed insulating plates, said insulating plates forming a widened elongated arcing slot which communicates with an adjacently disposed narrow arcing slot, one or more U-shaped magnetic inserts biasing the arc during high instantaneous values of current away from said narrow arcing slot and means for forcing the arc during low values of instantaneous arcing current into said arcing slot.

Another object of the present invention is the provision of an arc extinguishing unit of the type described in the aforesaid patent with means for preventing the burning and wearing of the walls forming the entrance to the narrow arcing slot in which the are ultimately forced to effect its extinction.

It is another object of the present invention to provide an arc extinguishing structure of the narrow slot type, in which provision is made for the presence of one or more series coils, the disposition of said one or more series coils being such that during relatively high instantaneous values of current the arc column is biased away from the entrance to said narrow arcing slot, and during relatively low instantaneous values of arcing current the biasing action exerted by said one or more series coils is reduced to permit the arc column to be forced into said narrow arcing slot to effect its extinction.

It is also an object of my invention to use any of the above mentioned biasing means either separately or in combination, and to use them in such a manner either in a liquid breaker or in a gas blast type breaker.

It is another object of my invention to use series biasing coils with an extinguishing structure of the foregoing type and draw the arc in said structure so that it is substantially under the influence of the magnetic field produced in the interior of said coils.

Another object of my invention is to provide an arc extinguishing structure of the aforesaid type utilizing a series coil to bias the arc column, and to position the arc column relative to said series coil adjacent a line drawn between the turns on one side of said coil.

By my showing some embodiments of my invention as specifically applied to a liquid breaker of the type described in the aforesaid patent, I do not mean to restrict its application only to a liquid breaker, for it is obvious that in its broad er aspects it is applicable to a breaker operating in other mediums than a liquid, such as air.

Other objects and advantages relate to details of the interrupter structure whereby the aforenamed objects are obtained and will appear more fully in the following description taken in connection with the accompanying drawings in which:

Figure 1 is a side elevational view, partially in section, of two series arc extinguishing units embodying my invention;

Fig. 2 is a sectional view of the lower are extinguishing unit taken substantially along the line IIII of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is a cross-sectional view taken substantially along the line III-III of Fig. l and looking in the direction of the arrows;

Fig. 4 is a cross-sectional view taken through an arc extinguishing unit similar to the are extinguishing units shown in Fig. 1 and embodying a modification of my invention;

Fig. 5 is a perspective view of an arc extinguishing unit similar to the arc extinguishing units shown in Fig. 1 but illustrating a further embodiment of my invention, and shown with some parts omitted for clarity;

Fig. 6 is a cross-sectional view taken substantially on the line VIVI of Fig. 5 and looking in the direction of the arrows;

Fig. '7 is a perspective View of another are extinguishing unit sim lar to the arc extinguishing units shown in Fig, 1, but containing a further embodiment of my invention and omitting some of the parts for clearness; and

Fig. 8 is a cross-sectional view taken substantially on the line VIII-VIII of Fig. 7 and looking in the direction of the arrows.

With particular reference to Fig. 1, the ref erence numeral l designates a cylindrical strain casing, only a part of which is shown, which forms part of a tank structure filled with a suitable arc extinguishing liquid, such as oil, and in which is disposed an arc interrupting assemblage, generally indicated by the reference numeral 3. The are interrupting assemblage 3 comprises one or more serially related arc extinguishing units, the latter generally being indicated by the reference numeral 5, and disposed in a superimposed spacial relation, being connected together by suitable insulating tie rods 1'. The are extinguishing units 5 are spaced a suitable distance apart by insulating spacing sleeves 9 which surround the insulating tie rods 7. The insulating tie rods I extend through the arc extinguishing units 5 and are surrounded therein by insulating sleeves l I, Fig. 3.

Each arc extinguishing unit 5 is composed of a plurality of suitably shaped insulating plates. Clamping nuts [3 screwed upon the insulating tie rod 1 and cooperating with the insulating spacas more clearly shown in '7 ing sleeves 9 serve to compress the insulating plates forming each arc extinguishing unit 5. The two arc extinguishing units 5, composing the arc interrupting assemblage 3, are suspended by means of metallic hanger rods l5 from a cover plate of the tank, not shown. Insulating sleeves l1 surround the metallic hanger rods l5 and serve to space the arc interrupting assemblage 3 a suitable distance below the surface of the arc extinguishing liquid which fills the tank.

Each arc extinguishing unit 5 has a metallic top plate I9. The metallic top plate l9 has bored therein a circular aperture 2| in which is screwed a guide bushing 23 which guides the motion of an insulating piston generally indicated by the reference numeral 25 which passes therethrough. Each metallic top plate [9 is provided with a rectangular aperture 2'! (see Fig. 1) through which extends a stationary contact 29. The stationary contact 29 is secured by a screw 3| to a resiliently mounted metallic strip 33 which extends transversely across the metallic top plate H] as more clearly shown in Fig. 2. The metallic strip 33 is resiliently mounted upon the metallic top plate I 9 by means of two stud bolts 35, around which are encircled compression springs 31 as shown in Fig. 1.

A flexible conductor 39 which leads to a line terminal of the interrupter, not shown, is fastened by a'stud bolt 4| to the resiliently mounted metallic strip 33 as more clearly shown in Fig. 1. Disposed within the arc extinguishing unit 5 is an upper metallic arcing born 43 which is secured by screws 45 to the metallic top plate IS. The metallic top plate 19 is suitably bored to provide two discharge vents 41 (see Fig. 2) which extend through the top plate I 9 and also through the upper metallic arcing horn 43, the purpose of which will appear more fully hereinafter.

. The metallic top plate I9 is also provided with a discharge vent 49 at the extreme left of the arc extinguishing unit 5 as viewed in Fig. 1. Each arc extinguishing unit 5 also has a bottom insulating plate 5| which is provided with a circular aperture 53 through which is screwed a guide bushing 55 which also serves in conjunction with the guide bushing 23 to guide the reciprocating motion of the insulating piston 25. A lower metallic arcing horn 51 is disposed upon the top surface of the bottom insulating plate 5| and suitably secured thereto by stud bolts 59 as more clearly shown in Fig. 1. A conductor stud Bl serves to electrically connect the lower metallic arcing horn 5'! to a flexible conductor 63, the

.- other end of which is secured to the resiliently mounted metallic strip 33 of the lower are extinguishing unit 5 by means of the stud bolt 4! as clearly shown in Fig. 2.

The movable contact is secured by a metallic cylindrical portion 61 to the insulating piston 25. The insulating piston 25 comprises an insulating rod 58 around which are disposed a plurality of insulating washers 19 and 8! of different external diameters which form a corrugated piston surface as clearly shown in Fig. 1. A metallic tubular coupling 65 is secured to the insulating rod 68 and is in electrical contact with the metallic cylindrical portion 5?. A flexible conductor H is secured at one end by the spanner nut 13 to the metallic tubular coupling 69, and the other end is secured by the stud bolts '15 to the resiliently mounted metallic strip 35 of the lower arc extinguishing unit 5.

In the closed circuit position of the interrupter the electrical circuit therethrough comprises an external line terminal, not shown, the flexible conductor 39, the stud bolt 4!, the resiliently mounted metallic strip 33, the stationary contact 29, the movable contact 65, the metallic tubular coupling 59, the flexible conductor H, the stud bolts '55 of the lower arc extinguishing unit 5, from which the electrical circuit passes through the lower arc extinguishing unit 5 in a manner similar to that already described in connection with the upper arc extinguishing unit 5. When the insulating piston is moved downward by suitable means, not shown, the movable contact 85 separates from the stationary contact 29 to draw an arc therebetween. The electrical circuit now through the interrupter is the same as that previously described with the exception that an arc interposed between the stationary contact 29 and the movable contact 65.

Positioned just below the metallic top plate 59 is a top insulating plate 83. The top insulating plate 83 is provided with a circular aperture 85 (see Fig. 1) which is in alignment with the discharge vent 49 bored in the metallic top plate [9. The top insulating plate 83 is also suitably shaped to permit the upper metallic arcing horn 43 and the stationary contact 29 to extend therethrough to the interior of the arc extinguishing unit 5. The top insulating plate 83 is also suitably shaped to permit the insulating piston 25 to pass therethrough.

Immediately below the top insulating plate 33 is a pocket insulating plate 87. This insulating plate is called a pocket insulating plate because it is provided with a plurality of pockets or recesses 88, as more clearly shown in Fig. 3, which are positioned along the walls forming the sides of the large arcing slot indicated by the reference numeral 93 in Fig. 3, and also along the walls forming the sides of the narrow arcing slot 95 as shown in Fig. 3. pockets or recesses 83 is to have relatively large available portions of arc extinguishing liquid suitably disposed along the walls forming the sides of the large and narrow arcing slots 93 and 95 to be reacted upon by the arc. Each pocket insulating plate 8! is provided with a barrier 89 (see Fig. 1) which prevents the are from being swept into the rear discharge vent 9'! shown in Fig. 1. The are is held by the barriers 89 in the narrow arcing slot 95 and is not permitted to be forced into the rear discharge vent 91.

Immediately below the pocket insulating plate 81 is a guard insulating plate ill. The plate 9! is called a guard insulating plate because it prevents the are from coming in contact with a U-shaped insert 99 of magnetic material which is embedded in an insert insulating plate 92, the latter being positioned between two guard insulating plates 9 5. Below the second guard insulating plate 9! is a pocket insulating plate 87.

Following the pocket insulating plate 91 is a guard insulating plate 9!, an insert insulating plate 92, a guard insulating plate 91, a pocket insulating plate 31, and so on with these respective groupings to the bottom of the stack.

When the respective plates are aligned and compressed into a stack to form the arc extinguishing unit 5 it will be noticed that the insert insulating plate 92 (see Fig. 3) and the guard insulating plates 9|, the shape of these plates being identical, form a circular longitudinal passage IUI through which the insulating piston 25 passes, and a communicating adjacently disposed longitudinal large arcing slot 93, which in The purpose of these turn communicates with an adjacently disposed longitudinal narrow arcing slot 95, the latter communicating by means of the passages through the two guard insulating plates 9| and the insert insulating plate 92 with the rear discharge vent 91.

For a more detailed description of the shape of the respective insulating plates reference may be had to the aforesaid Patent No. 2,138,382, in which are included plan and side views of the insulating plates and the metallic top plate which form each of the arc extinguishing units 5.

When the insulating piston 25 moves downward to separate the movable contact 65 from the stationary contact 29, an arc is formed therebetween. During high instantaneous values of arcing current the cross-sectional area of the arc will correspondingly be large, and its entrance into the narrow arcing slot will be prevented because of its large cross-section. In the aforesaid patent the arc Was constantly biased toward the narrow arcing slot 95 by the presence of U-shaped magnetic inserts in some of the insulating plates. This constant biasing of the arc toward the narrow arcing slot 95 tended to result a burning and wearing of the walls forming the entrance Hi3 (see Fig. 3) to the narrow arcing slot 95, which tendency toward burning and wearing tended to change the value of the low instantaneous current which was permitted to enter into the narrow arcing slot 95.

In the embodiment of my invention shown in l, 2, and 3 I have omitted the U-shaped netic inserts which were used in the aforesaid patent, and instead have provided the U-shaped magnetic inserts 99. I have found that during high instantaneous values of arcing current the magnetic field surrounding the arc is so distorted by the presence of the ,U-sh-aped magnetic inserts 99 that the arc is biased away from the entrance I93 to the narrow arcing slot 55. Thus the walls forming the entrance I03 are not burned nor worn. However, when the instantaneous value of the arcing current falls to a relatively low value the biasing action exerted by the magnetic inserts 99 away from the slot 95 diminishes to permit the liquid flow, caused by the downward movement of the insulating piston 25 into the interior of the arc extinguishing unit 5, to carry the arc to the left as viewed in Fig. 1 toward the rear discharge vent 91.

It is apparent that not only is the biasing action exerted by the U-shaped magnetic inserts 99 less during low instantaneous values of arcing current, but also the cross-section of the arc has decreased sufiiciently to permit the entrance of the are into the narrow arcing slot 95. Two forces come into play during low instantaneous values of current to bias the arc toward the narrow arcing slot 95 when the biasing action of the magnetic insert 99 away from the narrow slot 95 decreases. One of these forces is the liquid flow out of the arc extinguishing unit 5 through the rear discharge vent 91. This liquid flow is caused by the downward movement of the insulating piston 25 since the volume thereof is greater than the volume of the metallic tubular coupling 59 which was disposed in the are extinguishing unit 5 during the closed position thereof. Consequently, when the insulating piston 25 moves downward during a circuit opening operation liquid is displaced out of the arc extinguishing unit 5 out through the rear discharge vent 91, and this flow of liquid tends to move th are into the narrow arcing slot 95.

A second force which moves the arc laterally into the narrow arcing slot 95 is the inherent tendency of the arc to curve outward in the direction of the narrow arcing slot 95.

The method of arc extinction used is identical to that described in the aforesaid patent, namely the positioning of the arc in the large arcing slot 93 during high instantaneous values of current and during this time providing a longitudinal sweeping of arc extinguishing liquid longitudinally of the arc and upwards through the discharge vents 41 which extend through the upper metallic arcing horn 43. Consequently, products of decomposition of th liquid caused by the arcing are swept freely out'of the arc extinguishing unit through the discharge vents ll and yet the continuity of the arc itself during high instantaneous values of current is not disturbed. However, when the instantaneous value of the arcing current reaches a relatively low value the cross-section of the arc will be small enough to permit it to be carried into the narrow arcing slot 95, it being remembered that at this time the biasing action exerted by the U-shaped magnetic inserts 99 away from the entrance I03 has fallen to a low value.

Consequently, during low instantaneous values of current the liquid flow and the inherent bending of the arc will force the are into the narrow arcing slot 95, its cross-section now being sufliciently small to permit its entrance therein.

- When the arc is carried into the narrow arcing slot 95 it reacts upon the liquid retained in the pockets 88 disposed along the walls of the narrow arcing slot 95. The reaction of the are upon the liquid contained in these pockets 88 causes a strong cross-blast of oil and gas through the arc. The gas thus produced may escape through the arc toward the rear discharge vent 97, and the gas and liquid particles thus formed together with the flow of liquid created by the movement of the insulating piston is sufficient to extinguish the are at a current zero.

It is thus apparent that the arc is subjected to a strong flow or blast when in the narrow slot at and near current zero, as compared with the lesser flow which does not substantially disturb the are when it is held by the magnetic field in the wider slot during high instantaneous values of arc current.

In the embodiment of my invention shown illustrated in Fig. 4 there are provided two U- shaped inserts of magnetic material I05 and I01. The complete arc extinguishing unit, of which Fig. 4 is a cross-sectional view, is not shown; but it is of a type similar to the two arc extinguishing units 5 already considered in connection with Fig. 1. The two magnetic inserts I05, I01 are embedded in an insulating plate I04, which is similar in shape to the insert insulating plate 92 described in connection with Fig. 3.

It will be observed that a cut taken through the magnetic insert I05, say on the line A--A, will show a greater cross-sectional area than would a cut taken through the magnetic insert I01. say taken on the line BB, the purpose for which will appear hereinafter. It will also be noted that the air gap between the two legs I09, III of the magnetic insert I0! is less than the air gap between the two legs I I3, I I5 of the magnetic insert I05, the purpose for which will also appear hereinafter.

When the arcing current has a high instantaneous value, that is during the peak of the alternating current wave, the magnetic insert I01 will saturate, but the magnetic insert list will not saturate. Therefore the magnetic insert I05 will predominate during high instantaneous values of current to hold the are away from the entrance I03 to the narrow arcing slot 95. During relatively low instantaneous Values of arcing current, on the other hand, neither of the magnetic inserts I05, I01 will saturate, and due to the smaller air gap between the legs I09, III of the magnetic insert I01 the magnetic insert I07 will now predominate to force the are through the entrance I03 into the narrow arcing slot 95, where extinction will occur in a manner previously described in connection with Fig. 1.

It is therefore seen that by the suitable configuration and disposition of the magnetic inserts I95, I01 complete control of the lateral movement or the arc is obtained as a function of the instantaneous value of arcing current. During high instantaneous values of current the arc is biased away from the narrow arcing slot 95. During low instantaneous values of arcing current the arc is biased toward the narrow arcing slot 95. It is obvious that fluid flow and the inherent tendency of the arc to curve toward the narrow arcing slot will assist the magnetic inserts I0'I to bias the are into the narrow arcing slot 95 during low instantaneous values of arcing current.

A further embodiment of my invention is shown in Figs. 5 and 6. Fig. 5 is a view in perspective, with some parts omitted for clearness, of an arc extinguishing unit 5 which may be identical to are extinguishing unit 5 described in connection with Fig. 1. Or it need not be identical, but merely of a type similar to the arc extinguishing unit 5 illustrated in Fig. 1, since the feature of my invention shown in this embodiment is susceptible of application on any similar type of arc extinguishing unit as will clearly appear from the description of this embodiment.

Secured by a stud bolt II6 to the resiliently mounted metallic strip 33 is a conducting strap which extends downward externally of the unit 5 and then upward again to form a turn II9 of a series biasing coil, generally indicated by the reference numeral H8. The strap then curves around the upper end of the unit 5 as at I2I to form a second turn I23 of the series biasing coil H0. The end of the second turn I23 is securely fastened to the upper conducting arcing horn 43 by a stud bolt I25. The top plate I21 of the unit 5 is made of insulating material in this embodiment of my invention instead of conducting material as was the case in Fig. 1, the purpose for which will appear hereinafter.

It will be clear that when the breaker i in its closed circuit position, with moving contact 65 in abutting engagement with stationary contact 29 (not shown in Fig, 5, refer to Fig. 1), the series biasing coil I it] will not be in series circuit with the electrical circuit passing through the breaker, it being shunted during this time.

When the breaker is opened by external operating mechanism (not shown) an arc is initially drawn between the moving contact 65 and the stationary contact 29 (see Fig. 1). However, this initially drawn are soon transfers to the upper arcing horn 43, leaving the stationary contact 20. But when the arc has transferred to the upper arcing born 43, the top plate I21 being made of insulating material, the electrical circuit now through the breaker includes the series biasing coil II 3. In other words, the electrical circuit through the interrupter unit 5 after the transfer of the are from the stationary contact 29 to the upper metallic arcing horn comprises (see Fig. 1 with Fig. 5) flexible conductor 39, resiliently mounted metallic strap 33, series biasing coil IIB, upper metallic arcing horn 43, the arc itself, moving contact 65 (the are not yet having transferred from the moving contact 65 to lower arcing horn 5?) metallic cylindrical portion 6?, tubular metallic coupling 69, flexible conductor II to the resiliently mounted metallic strap 33 of the lower unit 5, from whence it passes through the lower unit 5 in a similar manner to that already described in connection with the upper unit 5.

It is apparent that the are will readily transfer from the stationary contact 29 to the upper metallic arcing horn 63 because of the fluid flow, and also because of the inherent tendency of the arc to curve to the left, looking at Fig. 1.

Referring more particularly to Fig. 6, which is a cross-section through the unit 5 taken substantially on the line VIVI of Fig. 5, the direction of the arcing current is assumed, for purposes of discussion, to be downward through the unit 5 as indicated by the I at the reference point I25. Assuming this state of facts, the direction of the current through the series biasing coil H8 is as indicated.

The series biasing coil I I8 is so positioned with respect to the unit 5 that when the cross-section of the arc is large, and the arc is hence positioned outside the entrance IE3 to the narrow arcing slot 95, the magnetic field surrounding the arc interacts with the magnetic field set up outside the biasing coil H8 to force the are to the right, looking at Fig. 6, away from the entrance I03 to the narrow arcing slot 95. The are will reach its equilibrium position during high instantaneous values of current adjacent a straight line connecting the two sides I33, I35 cf the respective turns I23, MS of the series coil HS. This equilibrium position will obviously be a position where the arc will not be disturbed by the magnetic field inside nor outside of the coil H3, and it is readily apparent that the disposition of the coil H8 with respect to the unit 5 may be such to thus control the lateral movement of the arc during relatively high instantaneous values of current.

When the instantaneous value of current decreases, that is approaching a current zero, the biasing action exerted by the coil H8 will correspondingly decrease to permit the fluid flow and the curving tendency of the arc to carry said are through the entrance I83 into the narrow arcing slot 95, in which extinction will follow as previously described.

It would, of course, be possible to have the coil II8 constantly in series circuit and not be shunted out during the closed circuit position of the interrupter; however, this leads to unnecessary heating so the above arrangement is considered preferable.

The embodiment of my invention shown illustrated in Figs, '7 and 8 is very similar to the embodiment shown in Figs. 5 and 6. However, the arc, the position of which is indicated by the reference numeral I38 in Fig. 8, is drawn within the coil I31, and in this embodiment of my invention is acted upon by the magnetic field set up within the series coil I31.

It will be noted that the current flows through the series coil I31 in a different direction than in the case of the series coil I IS in Figs. 5 and 6.

This change in direction of the current through the series coil I31 is necessary for the control of the lateral movement of the arc during high instantaneous values of current, as an examination of Fig. 8 will readily disclose.

In 8 an arbitrary direction of arcing current has been assumed to show the reaction upon the arc I39 by the magnetic field set up within the series coil I537. The arrows I39 indicate schematically the forces acting upon the arc I30 by the half-turns of the coil I31. The resultant of these forces will, of course, be to the right away from the entrance I03 to the narrow arcing slot 95.

The shunting out of the series biasing ccil I31 during the closed position of the breaker is the same as in the preceding embodiment of my invention. The electrical circuit through the breaker upon the opening thereof is the same as that described in connection with the previous embodiment of my invention. Consequently, during high instantaneous values of arcing current the are will be forced to the right by the series biasing coil I31 away from the entrance 53 to the narrow arcing slot 95. When the alternating current decreases in its instantaneous value, the biasing action exerted by the series biasing coil I31 will correspondingly decrease to permit fluid flow and the inherent curving of the arc to carry the are through the entrance Hi3 into the narrow arcing slot 95, where extinction iollows as previously described.

I am well aware that the above structures described cannot only be used individually, but may also be used in combination. By this I mean that series biasing coils may, for example, be used in an arc extinguishing unit in conjunction with magnetic inserts, similar to those employed in the modification shown illustrated in Fig, 4. Or series biasing coils may be used with magnetic inserts similar to those described in connection with Fig. 3. Other combinations, of course, exist, and the above are given only by way of example.

As previously mentioned my invention is susceptible of many applications, and is not confined to its application solely to liquid breakers.

Arc extinguishing units having gas evolving walls,

or having a source of any suitable gas, may be used in connection with my invention. I have shown its use on a liquid breaker merely for purposes of illustration.

Although I have shown and described specific structures it is to be understood that the same were for the purpose of illustration and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter, a substantially elongated arcing chamber, means for establishing an are adjacent the entrance to said elongated arcing chamber, means biasing said are into said elongated arcing chamber during at least a portion of the arcing time, and means biasing said are during relatively high instantaneous values of current away from the entrance to said elongated arcing chamber by disturbing the magnetic field surrounding said are.

2. In a circuit interrupter, an elongated arcing chamber, a restricted elongated arcing passage commiuiicating with said elongated arcing chamber, means for establishing an arc within said elongated arcing chamber adjacent the entrance to said restricted elongated arcing passage, means biasing said are into said passage during at least a part of the arcing period, and means biasing said are during relatively high instantaneous values of current away from the entrance to said elongated restricted passage by disturbing the magnetic field surrounding said are.

3. In an alternating current circuit interrupter, an elongated arcing chamber, a relatively narrow arcing slot communicating with said elongated arcing chamber, a stationary contact, a cooperating moving contact movable Within said elongated arcing chamber to establish an arc, said arc being established adjacent the entrance to said relatively narrow arcing slot, means biasing said are into said relatively narrow arcing slot during at least a part of the arcing period, and means biasing said arc during relatively high instantaneous values of current away from the entrance to said relatively narrow arcing slot by disturbing the magnetic field surrounding said arc.

4. In an alternating current circuit interrupter, an arc extinguishing unit submerged in an arc extinguishing fluid, means forming a substantially circular elongated arcing passage, a relatively narrow arcing slot communicating with said passage, a stationary contact disposed at one end of said passage, a cooperating moving contact movable within said passage to establish an arc, a piston member attached to said moving contact and movable therewith to cause fluid motion within said unit, said are being es-- tablished adjacent the entrance to said slot, means comprising said fluid motion for biasing said arc into said slot to effect the extinction thereof, and means biasing said are during relatively high instantaneous values of current away from the entrance to said arcing slot by disturbing the magnetic field surrounding said arc.

5. In a circuit interrupter, an elongated arcing chamber, means for establishing an are adjacent the entrance to said arcing chamber, means biasing said are into said arcing chamber during at least a portion of the arcing period, and means comprising magnetic material disposed adjacent said established arc to bias the same away from the entrance to said arcing chamber during relatively high instantaneous values of current.

6. In a circuit interrupter, a relatively elongated arcing chamber, a narrow arcing slot communicating with said chamber, means for establishing an are within said chamber and adjacent the entrance to said arcing slot, means biasing said are into said slot during at least a portion of the arcing period, and means comprising magnetic material disposed adjacent said are to bias the same away from the entrance to said slot during relatively high instantaneous values of current.

7. In an alternating current circuit interrupter, an elongated arcing chamber, means for establishing an are adjacent the entrance to said elongated arcing chamber, means biasing said arc into said arcing chamber during at least a portion of the arcing period, and means comprising one or more plates of magnetic material positioned adjacent said established arc to bias the same away from the entrance to said elongated arcing chamber during relatively high instantaneous values of current.

8. In a circuit interrupter, an arc extinguishing unit, said unit comprising a plurality of insulating plates, said plates forming an elongated arcing chamber and a narrow arcing slot com-- municating therewith, means for establishing an are within said chamber and adjacent the entrance to said slot, means biasing said are into said slot during at least a portion of the arcing period, and means comprising one or more plates of magnetic material positioned adjacent said established arc and biasing the same away from said slot during relatively high instantaneous values of current.

9. In a circuit interrupter, an elongated arcing chamber, means for establishing an are adjacent the entrance to said arcing chamber, means biasing said arc into said arcing chamber during at least a portion of the arcing period, and means comprising one or more substantially U-shaped plates of magnetic material to bias said arc away from said entrance during relatively high instantaneous values of current.

10. In a circuit interrupter, an elongated arcing chamber, a restricted elongated arcing passage communicating with said elongated arcing chamber, means for establishing an are within said elongated arcing chamber adjacent the entrance to said restricted elongated arcing passage, means biasing said are into said passage during at least a part of the arcing period, and means comprising one or more substantially U-shaped plates of magnetic material to bias said are away from said entrance during relatively high instantaneous values of current, the legs of said one or more substantially U-shaped plates of magnetic material at least in part surrounding said arc when it is initially established.

11. In an alternating current circuit interrupter, an arc extinguishing unit, are extinguishing fluid, means forming an elongated arcing chamber and a narrow arcing slot communicating therewith, means for establishing an arc within said arcing chamber and adjacent the entrance to said narrow arcing slot, means for creating motion of said fluid, means for directing said motion of said fluid against said arc in the direction of said narrow arcing slot, and means comprising one or more substantially U-shaped plates of magnetic material to bias said are away from said entrance during relatively high instantaneous values of current.

12. In a, circuit interrupter, an elongated arcing chamber with an elongated entrance thereto, means for establishing an arc adjacent said entrance, means comprising magnetic material for biasing said are into said chamber, means comprising magnetic material for biasing said are away from said entrance, the arrangement of all said magnetic material being such that during relatively high instantaneous values of current the outward biasing magnetic material predominates, and during relatively low instantaneous values of current the inward biasing magnetic material predominates.

13. In a circuit interrupter, an elongated arcing chamber with an elongated entrance thereto, means for establishing an arc adjacent said entrance, means comprising one or more substantially U-shape members of magnetic material for biasing said are into said chamber, means comprising one or more substantially U-shaped members of magnetic material for biasing said are away from said entrance, the disposition and arrangement of said members being such that during relatively high instantaneous values of current said second-mentioned biasing means predominates, and during relatively low instanc ous values of current said first-mentioned biasing means predominates.

14. In a circuit interrupter, an elongated arcing chamber with an elongated entrance thereto, means for establishing an are adjacent said entrance, means comprising one or more substantially U-shaped plates of magnetic material for biasing said are into said chamber, means comprising one or more substantially U-shaped plates of magnetic material for biasing said are away from said entrance, the shape of all said plates and the disposition thereof being such that during relatively high instantaneous values of current said are is biased away from said entrance, and during relatively low instantaneous values of current said arc is biased toward said entrance and into said elongated arcing chamber.

15. In a circuit interrupter, one or more serally related arc extinguishing units, arc extinguishing fluid, each unit forming an elongated arcing chamber and a narrow arcing slot communicating therewith, means for establishing an arc within said arcing chamber and adjacent the entrance to said narrow arcing slot, means for creating motion of said fluid, means for directing said motion of said fiuid against said are t ward said narrow arcing slot, one or more substantially U-shaped plates of magnetic material with a relatively large gap between the legs of said magnetic plate and a relatively large cross-section for biasing said are away from said entrance. one or more substantially U-shaped plates of magnetic material with a relatively small gap between the legs of said latter-mentioned magnetic plates and a relatively small cross-section for biasing said are through said entrance and into said narrow arcing slot, the arrangementbeing such that during relatively high instantaneous values of current the arc is positioned away from said entrance, and during relatively low instantaneous values of current the arc is forced by said fluid motion and said latter-men tioned magnetic plates through said entrance and into said narrow arcing slot to efiect the extinction thereof.

16. In a circuit interrupter, one or more series coils, said one or more series coils being connected in the interrupting circuit during at least a portion of the interrupting period, an elongated arcing chamber, means for establishing an are adjacent the entrance to said chamber, means biasing said are into said arcing chamber during at least a portion of the arcing period, one or more series coils being so disposed that they bias said arc away from said arcing chamber during relatively high instantaneous values of current.

17. In an alternating current circuit interrupter, one or more series coils, means for conmeeting said one or more series coils into the interrupting circuit during at least a portion of the interrupting period, a relatively elongated arcing chamber, a relatively narrow arcing slot communicating with said chamber, means for establishing an are within said chamber and adjacent the entrance to said slot, means biasing said are into said slot during at least a portion of the arcing period, said one or more series coils being so disposed that they bias the are away from said slot during relatively high instantaneous values of current.

18. In a circuit interrupter, one or more serially related arc extinguishing units, an arc extinguishing fluid, each unit forming an elongated arcing chamber and a narrow arcing slot comall) municating therewith, means for establishing an are within said chamber and adjacent the entrance to said slot, one or more series coils, means for connecting said one or more series coils into the interrupting circuit during at least a portion of the interrupting period, means for creating motion of said fluid, means for directing said motion of said fluid against said are toward said slot, said one or more series coils being so disposed that they bias the arc away from said slot during relatively high instantaneous values of current.

19. In a circuit interrupter, an elongated arcing chamber with an elongated entrance thereto, means for establishing an are adjacent said entrance, a series coil, said series coil being connected in series circuit during at least a part of the interrupting period, said series coil being so disposed that said are is established within said coil, means for biasing said arc into said entrance during at least a portion of the arcing period, said are being biased away from said entrance during relatively high instantaneous values of current by the magnetic field produced within said series coil.

20. In an alternating current circuit interrupter, one or more serially related arc extinguishing units, an arc extinguishing fiuid, each unit forming an elongated arcing chamber and a narrow arcing slot communicating therewith, means for establishing an are within said chamber and adjacent the entrance to said slot, a series coil, said ser es coil being connected in series circuit during the arcing period, means for creating fluid motion, means for directing said fluid motion against said are toward said arcing slot, said series coil being so disposed that said are is established within said coil, said arc being biased away from said entrance during relatively high instantaneous values of current by the magnetic field produced within said coil.

21. In a circuit interrupter, an elongated arcing chamber with an elongated entrance thereto, means for establishing an are adjacent said entrance, a series coil, said series coil being connected in series circuit during at least a part of the interrupting period, said series coil being so disposed that said arc is establshed adjacent a straight line connecting one side of the turns composing said coil, means for biasing said are into said entrance during at least a portion of the arcing period, said are being biased away from said entrance during relatively high instantaneous values of arcing current by the magnetic field created outside said coil.

22.111 an alternating current circuit interrupter, one or more serially related arc extinguishing units, an arc extinguishing fiuid, each unit forming an elongated arcing chamber and a narrow arcing slot communicating therewith, means fer establishing an are within said chamer and adjacent the entrance to said slot, a series coil, said series coil being connected in series circuit during the arcing period, means for creating fiuid motion, means for directing said fiuid motion against said arc toward said arcing slot, said series coil being so disposed with respect to said are that said are is established adjacent a stra t line connecting one side of the turns composing said coil, said are being afiected by the magnetic field set up external to said coil during r latively high instantaneous values of arcing current to bias it away from said entrance.

23. In a circuit interrupter, an arcing chamber, a passage leading from said chamber, means for establishing an are adjacent said passage, means for producing a flow of arc extinguishing fluid through said passage, and means for moving said are away from said passage during relatively high instantaneous values of current.

24. In a circuit interrupter, an arcing chamber, a passage leading from said chamber, means for establishing an are adjacent said passage, means for producing a flow of arc extinguishing fluid through said passage, and means for disturbing the magnetic field surrounding said are to move said are away from said passage substantially only during relatively high instantaneous values of arcing current.

25. In an alternating current circuit interrupter, arc extinguishing fluid, means defining a substantially closed arcing chamber, a passageway leading from said chamber for the ejection of fluid from said chamber, means for causing a flow of arc extinguishing fluid through said passageway, means for establishing an arc across said passageway Within said chamber, and magnetic means for displacing said are away from said passageway only during relatively high instantaneous values of arcing current, the arrangement being such as to minimize the effect of said flow on said are during relatively high instantaneous values of arcing current.

26. In a circuit interrupter, means for establishing an are, means for extinguishing said are by a cross-blast of arc extinguishing fluid, and magnetic means for minimizing said cross-blast only during relatively high instantaneous values of arcing current while permitting said arc to receive the full eifect of said cross-blast during relatively low instantaneous values of arcing current.

27. In a circuit interrupter, means for establishing an arc, means for extinguishing said arc by a cross-blast of arc extinguishing fluid, and magnetic means comprising magnetic material for minimizing said cross-blast only during relatively high instantaneous values of arcing current while permitting said arc to receive the full effect of said cross-b1ast during relatively low instantaneous values of arcing current.

28. In a circuit interrupter of the cross-blast type, means for establishing an arc, means for extinguishing said arc by a cross-blast of arc extinguishing fluid, and means disturbing the magnetic field surrounding said are to displace said arc substantially only during relatively high instantaneous values of arcing current, the effect of said displacement being to minimize the crossblast during high instantaneous values of current and to efiect an interruption of said are only during relatively low instantaneous values of current.

29. In a circuit interrupter, means for establishing an arc, means for producing a flow field of an arc extinguishing medium, the amount of said flow being diiferent at different points in said flow field, and magnetic means for moving said are during relatively high instantaneous values of arcing current to a point in said flow field where the flow is relatively of a small magnitude.

30. In a circuit interrupter, means for establishing an are, means for producing a variable fiow field of an arc extinguishing medium, and magnetic means for moving said are during relatively high instantaneous values of arcing current from a point in said flow field where the flow is high to a point in said flow field where the flow is relatively low, said magnetic means being operable to permit a return of said are during relatively low instantaneous values of arcing current to its original position to a point in said flow field of high flow.

31. In a circuit interrupter, an arc extinguishing fluid, a substantially closed arcing chamber, a vent in the wall of said chamber, means for creating a flow of said are extinguishing fluid through said vent and out of said chamber, means for establishing an are adjacent said vent within said chamber, a series conductor composed of solid conducting material, said series conductor being so disposed with respect to said are that during relatively high instantaneous values of arcing current said arc is moved away from said vent.

32. In a circuit interrupter, a substantially closed chamber, a vent in the wall of said chamber, means for establishing an arc adjacent said vent, arc extinguishing fluid, means for producing a flow of arc extinguishing fluid through said vent and out of said chamber, a series coil, said series coil being so disposed with respect to said arc that said arc is moved with respect to said vent during relatively high instantaneous values of arcing current.

BENJAMIN P. BAKER. 

